Pneumatic door-check



m5 Model.)

7 J. W. WETMORE.

PNEUMATIC DOOR CHECK.

Patented June 19, 1894;

v ll 5 u To all whom it may concern.-

UN TED STATES PATENT OFFICE.-

JEROME W. WETMORE, OF ERIE, PENNSYLVANIA, ASSIGNOR, BY MESNE ASSIGNMENTS, TO THE VAN WAGONER & WILLIAMS HARDWARE COMPANY, OF JERSEY CITY, NEW JERSEY.

PNEUMATIC DOOR-CHECK.

SPECIFICATION forming part of Letters Patent No. 521,747, dated June 19, 1894.

Application filed April 11, 1887. Serial No. 234,430. (No model.)

Be it known that I, J EROMEY W. WETMORE, a cltizen of the United States, residing at Erie city, in the county of Erie and State of Pennsylvania, have inventedcertain new and useful Improvements in Pneumatic Door- Checks; and I do hereby declare the following to be afull, clear, and exact description of the lnvention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanylng drawings, and to the letters of reference marked thereon, forming part of this specification.

My present improvements, relate to that class of pneumatic door checks, in which the air compressing piston does not leave the air cylinder, and one object sought by me is to obviate the use of toggle levers heretofore used in various forms, in connection with the piston for moving it outward in the cylinder, and also for imparting the thrust of a closing door to the piston. In accomplishing this end, I have for the first time provided the piston with a retractile spiral spring, which is normally housed within the air cylinder, but which when tensile strain is applied thereto, as when opening a door, will promptly and freely stretch, and vwhich will then by its retractile power, pull or draw the piston toward the front end of the cylinder, and cause a piston rod, or its partial equivalent, to so protrude from the cylinder, as to enable it to serve as an air cushioned abutment when struck by a swingingdoor when nearly closed or by a suitable pad, or other device carried by the .door. In some cases I use a single sprlng, but I have also provided for the use therewith, of a second or auxiliary spring,

within the air chamber, and which surrounds the first spring, and is arranged so as to cause the retraction of a tubular sleeve, operating in part as a piston rod, andwhich is interposed between the two springs, and said sleeve may be rigidly attached to the piston, or detached therefrom, but serving in either case when retracted, as the means by which the thrust of a closing door is borne by the piston and its air cushion. I have also provided for permitting a door to freely occupy its closed position, after its closing impetus has been fully checked. This has been heretofore accomplished by me,.in the use of an automatic relieving valve, but I have now devised an air passage, extending from near the closed rear end of the air chamber, forward a short distance, to an extent equal to say twice the thickness of the piston, whereby just prior to the end of'the inward stroke of the piston, the compressed air is permitted to freely pass by the piston and from the cylinder, and thus leave the door free to tightlyclose. This pressure relieving air passage is of special value for use with pistons having a valve which is opened by theretractile movement of the piston. It is obviously desirable to have such valve ports as small as possible for reducing liability of leakage to a minimum during the air compressing movement of the piston, and it is also desirable that the piston should move'freely from its position of rest. The said air passage enables the piston to be resistance other than thatdue to friction, even if there be no value in the piston, but with a .small valve port, the piston would be still protruding end of'the piston rod, and the shock or thrust was thereby communicated to thepiston andits aircushion. In my present door check, a similar mode of operation initially moved freely outward with but little is involved, but the piston is coupled to the door by means of a spring serving as a retractile link. p

After describing my improvements as illustrated in the accompanying drawings, the features deemed novel will be specified in the several clauses of claim hereunto annexed.

Referring to the drawings-Figure 1, illustrates a door frame, a partly opened door, a closing spring, and a door check embodying my present invention, applied to the under side of the frame cap and the inner face of the door. Fig. 2, is a plan view of the door check, as applied in Fig. 1, and shows the door in its frame, but with the cap of thelatterremoved. Fig. 3, illustrates the same, the door frame, and apartof the air cylind erbeing in section. Fig. 4, illustrates in section my door check in one of its simplest forms. Figs. 5 and 6, illustrate one of my checks as applied to the vertical face of a door frame cap, and the outer face of adoor. Fig. 7 illustrates in section the closed end of one of my air cylinders provided with an air relieving passage. Fig. 8 illustrates in section, one of my door checks having a main and also an auxiliary spring, and a tubular sleeve interposed between them, and movable outward independently of the piston. Fig. 9 illustrates in section one of my door checks having two springs, and an interposed sleeve which is directly attached to the piston. Fig. 10 is asectional view of the door check Fig. 9, on line 3 Fig.

11 illustrates one form of sleeve suitable for use in my door checks.

In Fig. 1, I show applied to the door, a well;

known form of closing spring at, and it is to be understood that although I always employ at least one spring in my door checks, and sometimes two, my springs may or may not serve efiiciently. as door closing springs.

That is to say, the prime function of my" main spring, is that of a flexible, 6Xt6I1Sl-:

ble, and freely retractile link for connection with the piston, so that the latter may be pulled forward in its cylinder by adoor during its opening movement, and hence said spring need have only enough retractile power to move the piston to the outer end of the cylinder, and in such case the use of a separate door closing spring will of course be desirable. Whether this spring be light or heavy in its retractile power, it will serve as an elastic flexible extension of the piston rod or sleeve, long after said rod or sleeve has had its front end properly located to receive the thrusting shock which is to be borne by the compressed air withinthe cylinder.

The air chamber A, is closed at its rear end,

and in Figs. 1, 2, 3 and 4, is shown to be provided with pivots m, and mounted in a bracket, to which it is pivoted at its front end 1 so that it may swing horizontally, and by which it may be mounted upon. the under side of a door cap. The piston is provided with a tubular sleeve 0, serving as a piston rod of such internal diameter, as will permit the free reception of the retractile spiral spring b, which is connected to the piston at the inner end of the sleeve or rod, and when in its normal retracted position, said spring is fully housed within the sleeve and air cylinder. The piston has the usual valve f, on

its inner face arranged to open freely while the piston is moving outwardly. The outer head of the air chamber has a circular opening in which the sleeve or rod 0, can slide freely to and fro, and said head prevents the piston from leaving the cylinder. The outer end of the spiral spring b, has an eye or a hook by means of which it may be readily connected with a door as clearlyindicated.

My door check as thus far described, is in one of its simplest forms, and it will be seen that when applied for use, and at rest, the spring I), will be wholly housed within the air chamber, and that during the initial opening movement of the door, the spring will be freely extended until the retractile strain or tension is sufficient to move the piston, whereupon the latter will continue to move until the piston strikes the front head of the cylment of the door. I accomplish this,.as shown in Fig. 7, by means of an air duct Z, extending from a point 0, adjacent to the innerface of the rear or closed endof the cylinder, forward, to a point p, a short distance, which is somewhat greater than the thickness of the piston, so that as soon as the piston passes the point p, the compressedair can pass outward by the piston, into the open front end of the cylinder.

Iam aware that in one type of. door checks an air cylinder has been heretofore employed, which was practically closed at both ends, because the piston rod was embraced by a gland packing, and said cylinder was provided at its front end, with a series of longitudinal scores or grooves cut or formed at the inner surface of the cylinder, which operated as relieving passages for enabling the always confined and permanent fluid contents of the cylinder, to resume an equilibrium of pressure on both sides of the piston,

at the termination of each outward stroke.

I am also aware, that British Letters Patent No. 5,925 of 1883, describes a door checking device embodying a cylinder provided with two ports, connected by a longitudinal duct or passage, but in that case said ports are located so near to both ends of the cylinder, that one of them, would be promptly uncovered at thebeginning of the inward stroke of the piston. Said patent relates to liquid cushioning, .and hence the construction referred to, might serve a good purpose, butin my device, the ports and air passage are es- .sentially, all located near the inner or closed end ofthe cylinder, so that the air checking ICC is all performed before the piston reaches the front port, and then when the latter is uncovered, the check is released, for permitting a thoroughly checked door, to freely close. 1

When my door checks are to be applied to the vertical side of a door frame cap, they are arranged as illustrated in Figs. 5 and 6. The air cylinder D, differs from the cylinder A, only in being hinged atits rear end to its bracket m, and the outer end of the spring I), is connected to asuitable upwardly curved arm e, projecting from the side of a door at 1ts top, so that in opening and closing the door, the operation of the door check will be the same as already described, the upwardly curved portion of the arm e, striking against the outer end of the piston rod or sleeve. It will be readily seen that the spring b, may be normally quite short, and yet readily extensible to a considerable length, and that the door check may be connected to a door, at a point sufficiently remote from its hinges, to

avoid undue strain on the latter, when the piston is struck by the door on which a pad, composed of leather, for instance, may be used to good advantage, at the points of contact with the piston sleeve.

In such door checks as are to be'relied upon for closing doors, the spring 6, should be stronger than would otherwise be needed, and I supplement said spring by another, p-

' erating as an auxiliary spring, which can be somewhat varied in its application and arrangement, without departure from this portion of my invention; as, for instance, in Fig. 8,v the spring I), is attached at its inner end to the inner end of a sleeve a, nearly tubular in form, as shown in Fig. ll. Outside of said sleeve is the auxiliary spiral spring 1', which at its ,inner end is coupled, as 'at q, to the piston, and at its outer end it is coupled at 7.0, to

the outer end of the piston sleeve 0, so that when the spring I), is pulled outward, it pulls the sleeves outward, and this in turn pulls outward on the auxiliary spring 2', and causes the piston to move in the same direction. When under the extremest tension, the spring '6, and the sleeve 0, may be drawn almost wholly outside of the air chamber, the piston being confined against withdrawal by its contact with the annular front head of the cylinder. As soon as tension is relieved, the springs and the sleeve promptly resume their normal positions as fully as possible, but of course more or less protruded from the cylinder, the sleeve 0, then being read yto operate in receiving the thrust from the door, and to impart the shock to the piston precisely as when said sleeve is attached firmly to the piston, as in the case of the sleeve rod 0, beforev described.

Instead of permitting the auxiliary spring to protrude from the air cylinder, I sometimes restrict it to the space between the piston, and the annular outer head of the cylinder, as illustrated in Figs. 9 and 10, wherein, as

the interior of the piston sleeve, a laterally curved but straight plate h, which is attached to the spring at two or more points, as at g,

so thatsaid plate may be moved outward, and slide back again, with the spring. Instead of being a narrow straight, but laterally curved, plate, said plate it may be nearly tubular, and of the form illustrated in Fig. 11, in which case it would, when protruded from the piston rod, support the inner spring when extended in like manner, as if it were a telescopic' extension of the piston sleeve, or as when organized as in Fig. 8.

Having thus described my invention, I claim as new. and desire to secure by Letters Patent.

1. In a pneumatic door check, the combination substantially as hereinbefore described, of an air cylinder and its piston, a piston sleeve or rod, and a retractile spring which is attached to the piston and serves as a flexible, extensible andretractile extension of the piston sleeve or rod, for pulling the latter and the piston, outwardly in the cylinder and presenting the outer end of said sleeve or rod in position to receive the thrusting shockincident to the closing of a door, and enabling said shock to be borne by air, compressed within the cylinder. I

2. In a pneumatic door check, the combination substantially as hereinbefore described, of an air cylinder, a piston, a hollow sleeve, or piston rod, and a retractile spiral spring normally housed within said, sleeve or rod, and serving as a, flexible, extensible, and retractile link, by which, during the opening of a door, the piston is moved forward in the cylinder, and the piston rod or sleeve projected beyond the open end of the cylinder for enabling it to receive and impart the shock of a closing door to the piston and air cushion within the cylinder. I

3. In a pneumatic door check, thecombination substantially as hereinbefore described, of an air. chamber, a piston, a spiral spring serving as a flexible, extensible, and retractilelink, by which the piston is moved outwardly in the cylinder, during the opening movement of a door, an auxiliary spiral spring IIO within said cylinder, surrounding the other and outward at the open end of the cylinder, [0 substantially as shown and described.

In testimony whereof I affix my signature in presence of two witnesses.

JEROME W. WETMORE.

Witnesses:

WM. R. HAYES, W. P. CoWELL. 

